Spring driven timer

ABSTRACT

In a spring driven timer a partially transparent housing is provided for enclosing a main spring, a gear train, an escapement, and a bell-sounding hammer. A drive shaft passes through the housing, supported by a bearing on a wall of the housing. The shaft supports at one end a timing cam and a hammercocking cam, and supports at its other end a bell adapted to be sounded by said hammer and an upper case member adapted to be rotated manually for setting said timer by initially adjusting the angular position of said drive shaft. A lost motion connection between a stop lever rotatably mounted on the shaft and a stop dog secured to the shaft for rotation therewith, permits 360* rotation of the shaft during its initial adjustment.

United States Patent [191 Bassett Aug.6, 1974 SPRING DRIVEN TIMER [75]Inventor: Ronald M. Bassett, Chicago, Ill.

[73] Assignee: International Register Company,

Spring Grove, Ill.

[22] Filed: Dec. 11, 1972 21 Appl. No.: 313,967

[52] U.S. Cl. 58/2l.l3 [51] Int. Cl. G04f 3/02 [58] Field of Search58/21.]3, 22.9, 39.5

[56] References Cited UNITED STATES PATENTS l,l53,466 9/1915 Tuerk58/21.]3

Primary Examiner-Lawrence R. Franklin Attorney, Agent, or FirmHill,Gross, Simpson, Van Santen, Steadman, OHara & Simpson l 5 7 ABSTRACT Ina spring driven timer a partially transparent housing is provided forenclosing a main spring, a gear train, an escapement, and abell-sounding hammer. A drive shaft passes through the housing,supported by a bearing on a wall of the housing. The shaft supports atone end a timing cam and a hammer-cocking cam, and supports at its otherend a bell adapted to be sounded by said hammer and an upper case memberadapted to be rotated manually for setting said timer by initiallyadjusting the angular position of said drive shaft. A lost motionconnection between a stop lever rotatably mounted on the shaft and astop dog secured to the shaft for rotation therewith, permits 360rotation of the shaft during its initial adjustment.

4 Claims, 8 Drawing Figures PATENTEU AUG 61974 SHEET 1 OF 2 PATENTED M193.827. 232

sum 2 or 2 Fig. 5

SPRING DRIVEN TIMER BACKGROUND OF THE INVENTION 1. Field of theInvention The present invention relates to a spring driven timer, andmore particularly to such a timer which is settable to a selectedinterval by initially rotating a knob, and which rings a bell at theexpiration of the selected interval.

2. The Prior Art A number of spring driven timers have been developed inthe prior art, in which a knob or the like is rotated to select aninterval, after which an escapement is driven by a spring through a geartrain to permit the knob gradually to rotate back toward its initialposition. When the initial position is reached a hammer is released toring a bell, signifying that the selected interval has expired. It isdesirable to produce such spring timing mechanism as economically aspossible, and for this reason to arrange the component parts of such atimer so that they are multifunctional, thereby to reduce the totalnumber of parts in the mechanism, and to increase its efficiency ofoperation, while at the same time reducing its cost of manufacture.

It is also desirable to achieve the maximum accuracy possible, both insetting a selected interval and in timing out the interval. For maximumaccuracy in setting an interval, the indicia representing intervalswhich may be selected (such as minutes, for example) should be as farapart as possible, in terms of degrees of rotation of the selected knob.Then slight errors in the initial manual adjustments of the knob areminimized. To this end, it is desirable to permit the knob to beinitially set to any position within 360 of its rotation, so that theindicia are spread completely around the knob and the greatest possibleangle per unit of selected time interval is provided. For the samereason, it is desirable to have the control knob as large in diameter aspossible, in order to spread out the scale of selectable time intervalsas much as possible. However, the use of a larger knob, all other thingsbeing equal, increases the cost of the timer.

. SUMMARY OF THE INVENTION Accordingly, it is a principal object of thepresent invention to provide a timer apparatus in which an internalselecting knob may be initially adjusted to any position within 360 ofrotation.

Another object of the present invention is to provide a timer apparatusin which the selecting knob may be made large without increasing thecost of the apparatus.

A further object of the present invention is to provide a timerapparatus which employs the fewest possible component parts, and whichtherefore can be manufactured efficiently and economically.

Another object of the present invention is to provide a timer apparatuswhich is fully operative in any position, so that the timer may beplaced in any desired attitude.

A further object of the present invention is to provide a design ofhousing for the drive spring so that its condition can be inspectedduring an intermediate step in the manufacture of the timer.

These and other objects and advantages of the present invention willbecome manifest upon an inspection motion between said shaft and saidstop lever so as to allow 360 rotation of the shaft, a bell secured to asecond end of said shaft, and a cover member secured to said second endof said shaft and rotatable therewith, said cover surrounding said belland said housing and bearing interval-designating indicia on its outerperiphery.

BRIEF DESCRIPTION OF THE DRAWINGS Reference will now be made to theaccompanying drawings which:

FIG. 1 is a perspective view of a spring driven timer incorporating anillustrative embodiment of the present invention;

FIG. 2 is a vertical cross-sectional view, taken through the center ofthe apparatus of FIG. 1;

FIG. 3 is a horizontal cross-sectional view of the apparatus illustratedin FIG. 2, taken through the plane IIIIII;

FIG. 4 is a horizontal cross-sectional view of the apparatus illustratedin FIG. 2, taken through the plane IV-IV;

FIG. 5 is a partial vertical cross-sectional view taken through theapparatus of FIG. 1 taken through the cylindrical surface V-V shown inFIG. 3;

FIG. 6 is a plan view of the bottom of the gear housing, illustratingthe timing cam and the hammercocking cam in their initial positions;

FIG. 7 is a view similar to view 6 but with the cams in a differentposition; and

FIG. 8 is an exploded, perspective view of the stop lever and the stopdog.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1 aperspective view of a spring wound timer 10 is illustrated. The timer 10comprises an upper cover member 12 and a lower cover member 14, thelower cover member serving as a base of the unit, and the upper covermember being rotatable about a central vertical axis with respect to thelower cover member. The upper cover member 12 is provided with indiciaor marks 16 equally spaced around the periphery thereof and whichrepresents minutes of time to which the timer may be set with referenceto an index mark 18 provided on the lower cover member 14. Numerals 20are also provided on the upper cover member 12 to give meaning to theindicia 16.

The upper cover member is rotatable through 360 in order to set thetimer for any period up to 60 minutes, and the numerals 20representative of 5 minute intervals up to minutes duration are spacedequally around the periphery of the upper cover member 12. The timer 10is set by rotating the upper cover 12 until the index 18 is aligned withthe indicia l6 corresponding to a selected time interval. Subsequentlythe time remaining before the expiration of the selected interval iscontinuously indicated by the indicia 16 adjacent the index mark 18.

FIGS. 2 through illustrate the manner in which the various components ofthe timer are assembled. The gear train of the timer is maintained inposition between an upper frame plate 22 and a lower frame plate 24. Atransparent plastic housing cover 26 encloses a space 27 above the upperframe plate 22, and four legs 28, which are formed integrally with thehousing cover 26, serve to support the frame plates 22 and 24 in fixedrelation to the housing cover 26. The main spring 30 is disposed abovethe upper frame plate 22, within the space 27 enclosed by the cover 26.The cover 26 has an upper surface 32 and a peripheral sidewall 34surrounding the space 27. The shape of the cover 26 is elongated, withthe wall 34 having straight side portions 36 and arcuate end portions38. The side portions 36 overlie the upper frame plate 22, to maintainit in spaced parallel relation with the upper surface 32, and the endportions 38 are juxtaposed with the edge of the circular upper frameplate 22, and heat staked to form a lip 40 below opposed sections of theframe plate 22 to maintain it in position relative to the upper surface32. The lower frame plate 24 is maintained in position by virtue ofbeing trapped between the lower ends of the legs 28 and a surface 42provided within the lower cover member 14. A pair of screws 44 securetwo legs 28 to the lower cover member 14, while another pair of screws45 secure the other two legs 28 to the lower frame plate 24.

The gear train is mounted between the two frame plates 22 and 24 inconventional fashion, and the main spring 30 which is maintained incoiled relation within the space 27 has one end thereof engaged in anotch 46 within the drive shaft 48, and another end hooked about the endof an interior wall 50 of the housing cover 26. The wall 50 forms acircular loop which encircles the spring 30 and holds it in place duringassembly. The spring 30 is pre-wound approximately three turns prior toassembly so that there is a substantial torque constantly conveyed tothe shaft 48. The fact that the housing 26 is transparent aids in theassembly of the timer, as the position and condition of the spring maybe inspected until a bell 56 is placed in position.

The main bearing 52 is supported within an aperture disposed in thehousing cover 26 and a boss 54' surrounds the aperture in which thebearing is located and projects upwardly'from the upper surface 32, tosupport the central portion of the bell 56. The bell 56 has a U-shapedcross-section and surrounds the housing cover 26, the spring 30, and thegear train supported between the plates 22 and 24.

The main bearing 52 has a central aperture which receives the shaft 48,the central aperture having a counterbore at the lower portion thereof,and the shaft 48 being provided with an enlarged portion 53 joining withthe upper portion 55 of the shaft by a shoulder 54 located injuxtaposition with the shoulder formed at the end of the counterbore ofthe bearing 52. A bowed E- ring 56 is disposed in an annular notchsurrounding the outside of the bearing 52 and functions to urge thebearing 52 upwardly relative to the housing cover 26, to take up axialplay within the bearing 52, and to maintain the bell 56 tightly engagedwith the housing cover 26.

the frame plates 22 and 24 and the cover 26. The gear train is disposedbetween the frame plates 22 and 24 and is connected to the enlargedportion 53 of the shaft 48, by means of a main drive gear 58, whichencircles the shaft 48 and is adapted for rotation about the shaft 48.The gear 58 is in engagement with a gear 60 secured coaxially to alarger gear 62. The gear 62 is in engagement with a gear 64 which issecured coaxially to a larger gear 66. in similar fashion, the gear 66is in engagement with gear 68 which is connected for rotation with alarger gear 70. The larger gear 70 is in engagement with a pinion 72,which bears a saw toothed escapement ratchet wheel 73, forming a part ofan escapement mechanism 74. As a result of the action of the spring 30urging the shaft 48 to rotate back toward its initial position, all ofthe gears 60-72 are urged to rotate, but the action of the escapement 74limits the speed of rotation of the members of the gear train in themanner well understood by those skilled in the art. The escapement 74serves to control the precise speed of the gear train, so that therotation of the shaft 48 back to its initial condition takes place at aconstant angular velocity.

The escapement 74 comprises, in addition to the ratchet wheel 73, a pawl71 having a pair of dogs 75 for alternately engaging teeth of theratchet wheel 73. The pawl is mounted for oscillating rotation on ashaft 65, supported between the plates 22 and 24, and a plurality oflugs 77 grip a weighted bar 79, which is provided to add mass to thepawl 71. Three of the lugs 77 are disposed within a centrally locatedslot in the bar 79, and two others engage the side edges of the bar. Thepawl 71 is formed of plastic material, and the lugs 77 are heat stakedto retain the bar 79 firmly in position.

The various gears 60-72 are supported for rotation on shafts which areengaged in aligned apertures in the two frame plates 22 and 24.

The gear 58 is connected to the shaft 48 by means of a clutch which willnow be described. The shaft 48 has a shoulder 76 and a washer 78 is inengagement between the shoulder 76 and the gear 58. A second washer 80is disposed below the gear 58 and a resilient member 82 which functionsas a spring clutch is disposed on the shaft 48 above the washer 80. Thewasher 80 and the resilient member 82 have rectangular apertures whichare adapted to receive a rectangular crosssection portion 84 of theshaft 48, thereby keying the resilient member 82 to the shaft forrotation therewith. The washer 80 is fixed firmly co-rotatably to theshaft 48 and a projection or dog 86 projects radially outwardly from theremainder of the washer 80. The dog 86 functions as a stop dog, asdescribed below. The resilient member 82, which is keyed to the shaft48, exerts a sufficient force acting on the gear 58 so as to prevent theshaft 48 from overriding the gear 58, as the latter slowly rotates bythe action of the escapement 74. The force is low enough, however, so asto allow the shaft 48 to slip relative to the gear 58 as the shaft isinitially rotated to select a time interval.

The stop dog 86 cooperates with a stop lever 88, which extends upwardlythrough an aperture 90 provided in the lower frame plate 24. The stoplever 88 is integrally connected with a washer 92 which is mounted forrotation about a lower terminal portion 94 of the shaft 48 which liesjust below the rectangular cross-section portion 84. Accordingly,'thestop lever 88 is adapted for free oscillatory rotation relative to theshaft 48 within the limts of the aperture 90. The size of the aperture90 is selected to permit 360 rotation of the shaft 48, such rotationbeing limited in both directions by engagement of the dog 86 against oneside or the other of the stop lever 88. The angular extent of theaperture 90 is, therefore, approximately equal to the angular extent ofthe dog 86, plus twice the thickness of the lever 88.

The portion 94 of the shaft 48 is received in a circular aperture 95 inthe frame plate 24.

A hub 96 is secured to the bottom of the shaft 48, and a hammer-cockingcam 98 is fixed to the hub 96 for rotation therewith and with the shaft48. A timing cam 100 is supported on the hub for free rotationthereabout, between the hammer-cocking cam 98 and a flange 101 of thehub 96. The function of the hammercocking cam 98 is to cock a hammerarrangement, while the function of the timing cam 100 is to permitrelease of the hammer at the proper time, after the expiration of theselected timing interval.

A bellcrank 102 is mounted for rotation relative to the lower frameplate 24 on a stud 104. The bellcrank 102 has secured to it a camfollower pin 106 which extends downwardly through an aperture 108provided in the lower frame plate 24 and is adapted to bear on theperiphery of the timing cam 100.

A spring 120 is interconnected between an arm 122 of the bellcrank 102,and an aperture 124 provided in the lower frame plate 24. It urges thebellcrank 102 in a counterclockwise direction (as viewed in FIGS. 6 and7), but normally the crank 102 is prevented from rotating by virtue ofthe follower pin 106 bearing against the periphery of the timing cam100. When a notch 118 of the timing cam 100 is aligned in a positionshown in FIG. 6, the follower pin 106 bears against the end of the notch118, as illustrated in FIG. 6. When an interval has been selected andthe timer is operating, the follower pin engages a circular portion ofthe timing cam 100 and the bellcrank assumes the position illustrated inFIG. 7.

At the end of the selected interval, the notch 118 again becomes alignedwith the pin 106 and the bellcrank 102 is quickly rotated to theposition of FIG. 6. As the bellcrank 102 rotates, a foot 126 supportedthereon engages a hammer 128 supported on a stud 130 extending betweenthe upper and lower frame plates 22 and 24. A spring 132 is wound aboutthe stud 130 and has one end hooked around the hammer 128 and the otherend trapped behind one of the legs 28, to maintain the hammer 128rotated fully in its counterclockwise direction (as seen in FIG. 7)against the foot 126. When the bellcrank 102 rotates in acounterclockwise direction, the foot 126 bears against the hammer 128,urging it in a clockwise direction, and causing it to rotate about itsstud 130 sharply against the inner surface of the bell 56. In thismanner the bell 56 is caused to sound when the timing cam 100 hasreached the position illustrated in FIG. 6. In this position, the shaft48 has been rotated fully to its extreme clockwise position (as viewedin FIG. 6), where rotation is stopped by engagement of the stop lever 88against the stop dog 86.

The timing cam is constrained to rotate with the shaft 48 by virtue ofthe interconnection between the hammer cocking cam 98 and a studdisposed on the surface of the timing cam 100. The stud 110 isinterposed between two limiting fingers 112 and 114 on thehammer-cocking cam 98, so that as long as the stud 110 is adjacent oneof the fingers 112 and 114, the timing cam 100 is constrained to rotatewith the cam 98 in the direction which urges the limit finger intocloser engagement with the stud 110.

The hammer-cocking cam 98 has an inclined cam surface 116 adapted tobear on the follower pin 106 when the shaft 48 is initially rotated toselect a timing interval, thereby to cam the pin 106 out of engagementwith the notch 118.

When the upper cover member 12 and the shaft 48 are rotated to set aselected timing interval, the hammer-cocking cam 98 is rotated in acounterclockwise direction (as viewed in FIG. 6) so that the cam surface116 forces the follower pin 106 outwardly. The timing cam 100 isprevented from rotating during this period because the follower pin 106is in engagement with one of the sidewalls of the notch 118. By the timethe limit finger 112 reaches the stud 110, however, the follower pin 106has been cammed outwardly beyond the outer surface of the timing cam100, so that the timing cam is then rotated by means of the limit finger112 bearing against the stud 110. This occurs during the first fewdegrees of rotation of the upper cover member 12, and afterwards, thetiming cam is rotated with the cam 98 as far as necessary to select theappropriate time interval. Then the upper cover member is released andthe spring 30 is effective to return the shaft 48 and the upper covermember 12 to their initial positions, under the control of the geartrain and the escapement, rotating the shaft 48 in a clockwise direction(as viewed in FIGS. 6 and 7). The timing cam 100 is initially preventedfrom rotating because of the frictional force resulting from thefollower pin 106 bearing against its periphery, but when the finger 114engages the stud 110, the friction between the cam 100 and the followingpin 106 is overcome and the timing cam 100 is forced to rotate with thecam 98. This pause in the rotation of the timing cam 100 is for the sameangle of rotation of the shaft 48 as during cooking of the hammer, andtherefore does not affect the accuracy of the timer. Rotation of the cam100 continues until the notch 118 reaches the position illustrated inFIG. 6, whereupon the pin 106 falls into the notch 118 and causes thehammer 128 to strike the bell 56.

It will be seen from the foregoing description that the timer describedabove accomplishes the function of permitting 360 rotation of the covermember 12 in order to set a selected time period for the timer, and, asthe indicia are located on the extreme periphery of the upper covermember 12, their angular separation is a maximum, resulting in themaximum accuracy of repeatability of time interval settings. Economy isachieved in the present apparatus by enabling the upper cover member 12to doube as a cover and as a knob. There is, therefore, no need for aseparate interval-selecting knob.

The embodiment described above requires only a single main bearing 52,rather than the conventional arrangement in which two spaced bearingsare required. Axial alignment of the shaft 48 is assured because theflange 101 of the hub 98 is spaced just far enough to accomodate thethickness of the stop lever washer 92 and the thickness of the lowerframe plate 24. The follower pin 106 bearing heavily on the timing cam100 prevents any lateral play in the mechanism.

Because of the spring 132, which keeps the hammer 128 against the foot126, the timer apparatus may assume any attitude and the hammer 128remains operative to sound the bell. Preferably the flat outer surfaceof the lower cover member 14 is provided with an aperture to accomodatea nail head or a screw head when the timer is to be wall-mounted.

What is claimed is:

1. In a spring driven timer which is manually settable to select a timeinterval: an upper inverted cup-shaped cover having means centrallytherein securing it to the top of a vertically extending shaft; a basemember having a housing cover member mounted thereon and defining amechanism space above said base member and below said housing covermember; timer mechanism comprising spaced upper and lower frame platessupporting a timer gear train, the upper plate being mounted on saidhousing cover member and said lower plate being mounted on said basemember; said shaft extending downwardly through and being journaled insaid housing cover member and in said lower plate and having a lowerterminal portion extending below said lower plate into a space withinsaid base below said lower plate; a gear mounted corotatably on saidshaft in limited spaced relation above said lower plate and coupled withsaid gear train; a main spring coiled about said shaft above said upperplate and anchored at one end to said shaft and at its opposite end tosaid housing cover member; a bell carried by said housing cover memberoutside of said mechanism space; means for sounding said bell in onerotary position of said shaft and including actuating cam structurecarried by the lower terminal portion of said shaft below said lowerplate and effecting releasable coupling with a bell striker and actuatormounted on said lower plate; and means for limiting rotation of saidshaft to about 360 during manual setting of the timer by rotation ofsaid shaft through said upper cover and including a first limit membercorotatably secured to said shaft between said gear and said housingcover member and a second limit member comprising a plate mounted aboutsaid shaft below said lower plate and above said actuating camstructure, said second limit member having a stop lever projectingupwardly through an aperturein said lower plate and being engageable bya stop dog on said first limit member, said aperture being of a width tolimit movement of said lever in either rotary direction to about equalthe angular extent of said dog plus twice the thickness of the leverwhereby to permit the 360 rotation of the shaft.

2. A timer according to claim 1, wherein said upper cover has an annulargenerally vertically extending periphery carrying interval signifyingindicia, and said base member has an index reference mark with respectto which said indicia are settable by turning of said upper covermember.

3. A timer according to claim 1, wherein said housing cover member is oftransparent plastic and permits the position and condition of said mainspring to be inspected therethrough.

4. A timer according to claim 3, said bell comprising a U-shapedinverted cup-shaped member which surrounds said housing cover member andthe timer mechanism.

1. In a spring driven timer which is manually settable to select a timeinterval: an upper inverted cup-shaped cover having means centrallytherein securing it to the top of a vertically extending shaft; a basemember having a housing cover member mounted thereon and defining amechanism space above said base member and below said housing covermember; timer mechanism comprising spaced upper and lower frame platessupporting a timer gear train, the upper plate being mounted on saidhousing cover member and said lower plate being mounted on said basemember; said shaft extending downwardly through and being journaled insaid housing cover member and in said lower plate and having a lowerterminal portion extending below said lower plate into a space withinsaid base below said lower plate; a gear mounted corotatably on saidshaft in limited spaced relation above said lower plate and coupled withsaid gear train; a main spring coiled about said shaft above said upperplate and anchored at one end to said shaft and at its opposite end tosaid housing cover member; a bell carried by said housing cover memberoutside of said mechanism space; means for sounding said bell in onerotary position of said shaft and including actuating cam structurecarried by the lower terminal portion of said shaft below said lowerplate and effecting releasable coupling with a bell striker and actuatormounted on said lower plate; and means for limiting rotation of saidshaft to about 360* during manual setting of the timer by rotation ofsaid shaft through said upper cover and including a first limit membercorotatably secured to said shaft between said gear and said housingcover member and a second limit member comprising a plate mounted aboutsaid shaft below said lower plate and above said actuating camstructure, said second limit member having a stop lever projectingupwardly through an aperture in said lower plAte and being engageable bya stop dog on said first limit member, said aperture being of a width tolimit movement of said lever in either rotary direction to about equalthe angular extent of said dog plus twice the thickness of the leverwhereby to permit the 360* rotation of the shaft.
 2. A timer accordingto claim 1, wherein said upper cover has an annular generally verticallyextending periphery carrying interval signifying indicia, and said basemember has an index reference mark with respect to which said indiciaare settable by turning of said upper cover member.
 3. A timer accordingto claim 1, wherein said housing cover member is of transparent plasticand permits the position and condition of said main spring to beinspected therethrough.
 4. A timer according to claim 3, said bellcomprising a U-shaped inverted cup-shaped member which surrounds saidhousing cover member and the timer mechanism.